Do I have strong reference cycles here?

I have a BaseViewController which is subclassed by all other view controllers in my app.

I have some state variables which must be consistent across all view controllers, so I plan to write code for passing back-and-forth these state variables once in the BaseViewController. For this I'm providing a helper function pushStatefulViewControllerWithIdentifier() for forward passing and using StatePassBackDelegate for backward passing.

import UIKit

class BaseViewController: UIViewController, StatePassBackDelegate {

    class State {
        var connected = false
        var loggedIn = false
    }


    var state = State()
    weak var delegate: StatePassBackDelegate? = nil


    // MARK: Lifecycle
    override func viewWillDisappear(animated: Bool) {
        super.viewWillDisappear(animated)

        if self.isMovingFromParentViewController() == true {
            delegate?.passBackState(state)
        }
    }


    // MARK: StatePassBackDelegate functions
    func passBackState(state: AnyObject) {
        self.state = state as! State
    }


    // MARK: Helpers
    final func pushStatefulViewControllerWithIdentifier(identifier: String) {
        let vc = storyboard?.instantiateViewControllerWithIdentifier(identifier) as! BaseViewController
        vc.state = state
        vc.delegate = self
        navigationController!.pushViewController(vc, animated: true)
    }

}


protocol StatePassBackDelegate: class {

    func passBackState(state: AnyObject)

}

1. Do I have strong reference cycles here?
2. Should I instead use the singleton pattern here?